SECONDARY FLOCCULATED COLLOIDAL SILICA, METHOD FOR PRODUCING THE SAME AND ABRASIVE COMPOSITION USING THE SAME

摘要

PROBLEM TO BE SOLVED: To produce secondary flocculated colloidal silica which ensures a high polishing speed when used as an abrasive for a semiconductor device or the like, and to provide a method for producing the colloidal silica at a low cost. SOLUTION: The secondary flocculated colloidal silica is obtained by adding a flocculant for silica particles to monodisperse colloidal silica to form spherical flocculated secondary particles and by further adding active silicic acid to integrate the flocculated particles. The secondary flocculated colloidal silica particles have surface ruggedness, the ratio Y (X1/X2) of the geometric average particle diameter (X1) obtained from TEM (transmission electron microscope) transmission projected images to the equivalent particle diameter (X2) calculated from the surface areas of the silica particles is in the range of 1.3-2.5 and the geometric average particle diameter is in the range of 20-200 nm. The silica particles have superior properties as an abrasive in the surface polishing of electronic materials such as a semiconductor device.